Who is Betty Eakins from Sweet and Deadly and what is their importance?

Betty Eakins was a longtime employee of the Linton family. She only left their employ when her age made it impossible to keep working. Catherine remembers Betty fondly, though her opinions on race relations changed while she was in college. She was actually relieved when Betty retired. After Leona's death, Catherine meets Betty's son who is the new sheriff's deputy. They are initially uncomfortable with each other because of Catherine's relationship to his mother, but when Betty wants to see Catherine, her son makes these wishes clear. Catherine goes to see Betty, where she learns that Betty overheard a conversation between her father and an angry man a few days before her father's death. Catherine uses this information to figure out who the killer is and what his motives were.